body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
  background-color: #f0f2f5;
  color: #333;
  line-height: 1.6;
  margin: 0;
  padding: 0;
}

.container {
  max-width: 800px;
  margin: 40px auto;
  padding: 30px;
  background-color: #ffffff;
  box-shadow: 0 0 20px rgba(0, 0, 0, 0.1);
  border-radius: 12px;
}

h1 {
  text-align: center;
  color: #2c3e50;
  margin-bottom: 30px;
  font-weight: 600;
}

#log-area {
  margin-top: 20px;
  margin-bottom: 20px;
}

#log {
  box-sizing: border-box;
  width: 100%;
  height: 300px;
  padding: 10px;
  border: 1px solid #ddd;
  border-radius: 4px;
  font-family: monospace;
  font-size: 14px;
  resize: vertical;
}

.btn {
  display: block;
  width: 200px;
  padding: 10px 20px;
  background-color: #3498db;
  color: white;
  border: none;
  border-radius: 5px;
  font-size: 16px;
  cursor: pointer;
  transition: background-color 0.3s, transform 0.1s;
  margin: 0 auto;
  font-weight: 500;
}

.btn:hover {
  background-color: #2980b9;
  transform: translateY(-2px);
}

.btn:active {
  transform: translateY(0);
}

.btn:disabled {
  background-color: #bdc3c7;
  color: #7f8c8d;
  cursor: not-allowed;
  transform: none;
}

.btn:disabled:hover {
  background-color: #bdc3c7;
  transform: none;
}
